Fructose, found in fruit juice, is even more strongly linked to obesity and diabetes than glucose.
Most cells in the body can use glucose for energy, but only the liver can metabolize fructose. Glucose can be used throughout the body for energy, but fructose solely hits the liver.
When a large quantity of glucose is eaten, it circulates to your cells and the load is dispersed. This only leaves about 20% of the incoming glucose load for the liver to metabolize. Any extra glucose can be converted into glycogen for storage leaving a little remaining glucose around for fat storage.
This is not what happens when you consume a lot of fructose. An example of an excessive fructose load to the liver, is having a glass of orange juice daily. An 8-ounce glass of orange juice contains the sugars from 5-6 oranges. You would never eat 6 oranges in one sitting, so you shouldn’t be drinking the sugars from 6 oranges. Especially not in the absence of the beneficial fiber that a whole orange contains. Orange juice with pulp does not contain even close to the same amount of fiber as the whole fruit.
Large quantities of fructose put significant pressure on the liver. High fructose is more likely to cause fatty liver, the key problem of insulin resistance, compared to glucose.
The metabolism of alcohol is similar to that of fructose. Once consumed, tissues can only metabolize 20% of the alcohol leaving 80% delivered straight to the liver, where it is metabolized to acetaldehyde, which stimulates fat synthesis. The key take home here is that along with fruit juice, alcohol is also easily turned into a fatty liver. Excessive alcohol, categorized as more than 1-2 drinks daily, is also a risk factor for the development of metabolic syndrome.
In conclusion, fructose was once considered safe to intake in high doses because of its low glycemic index. But we now know that fructose exerts its toxicity mainly through long-term effects on fatty liver and insulin resistance. Fructose is five to ten times more likely than glucose to cause fatty liver.
Cutting back on all sources of sugar, including fructose and alcohol, and eliminate fruit juices from your diet. This is the best thing you can do for weight loss. Sugar are empty calories that provide you with no beneficial nutrients, and can lead to obesity and metabolic syndrome if you take in too much.
In collaboration with Elizabeth Stavros, ND.